Suspicious DLL Payload Dropped Under Non-Standard Assembly Directory (via file_event)

ATT&CK techniques

Lateral Movement

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
- T1021.003Distributed Component Object Model
- T1570Lateral Tool Transfer
Collection
C2
Exfiltration
Impact

What it detects

This rule detects the creation of a DLL under the non-standard C\assembly\tmp staging directory used by the DCOM Upload and Execute backdoor documented by Deep Instinct. The backdoor abuses the DCOM MSI install server to upload and load a managed assembly for remote code execution. Detecting this drop exposes lateral tool transfer before the payload is loaded into a victim process.

Reporting behind it

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Suspicious DLL Payload Dropped Under Non-Standard Assembly Directory (via file_event)

Pivot detection · T1570 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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